Chevy 2500 HD 6.0 question

[jkilroy]

I’m towing a 7500 lb. Cougar 28SGS. The truck I have is a 03 Silverado 2500 HD 6.0 with 4.10 rear. This rig tows fine in cooler weather with no A/C and fairly flat to moderate hills. When I pull in decent mountains and it’s hot the trans temp climbs past 200, and coolant goes to 230 range. As soon as I turn off a/c everything is fine. Has plenty of power I must say. I usually set rpm to 3000 and let it run.

So question is can I do anything to truck to help the problems? Can I put a cooler thermostat in it? I’ve already added a second trans cooler. It helped a little. A diesel is in my future but I’d like to pay off camper first if possible. They are so expensive.

[laknox]

jkilroy wrote:
I’m towing a 7500 lb. Cougar 28SGS. The truck I have is a 03 Silverado 2500 HD 6.0 with 4.10 rear. This rig tows fine in cooler weather with no A/C and fairly flat to moderate hills. When I pull in decent mountains and it’s hot the trans temp climbs past 200, and coolant goes to 230 range. As soon as I turn off a/c everything is fine. Has plenty of power I must say. I usually set rpm to 3000 and let it run.

So question is can I do anything to truck to help the problems? Can I put a cooler thermostat in it? I’ve already added a second trans cooler. It helped a little. A diesel is in my future but I’d like to pay off camper first if possible. They are so expensive.

All the other guys have given you excellent advice. On the RPM, though, you need to run that up into the 4's, that's where a gas engine makes the most power and will work "easier". At 3k, you're likely lugging the engine some and it will work "harder", even at a lower RPM. I've seen this with my own eyes on a trip with an old truck pulling a 3-axle GN up over Cajon Pass and Tehachapi. Not only did the engine run cooler at a higher RPM, mileage =improved= slightly. This was with a 600 RPM difference on a Turbo 400 with GearVendor O/D running the same gear with the O/D on and off. Don't be afraid to run the RPM up and hold it there in whatever gear you can hold. Downshift if you have to to keep that RPM.

I just checked, and that engine (2003 6.0l Vortec) specs at 300 h.p. at 4400 RPM and 360 lb ft torque at 4000 RPM. So, run her up to 4400 to get max hp.

Lyle

[garyp4951]

I would look an electric radiator/condenser fan that comes on only when the ac is switched on, or put it on a manual switch, if you have room for it.

[Ralph_Cramden]

Buy a diesel....better yet get two......

Why not start at the other end of the spectrum. Thermostats go bad be it sticking open or closed, or loose their calibration.

Assuming its OEM its 15 years old. A $15 part and 15 minutes. On a GM you can actually get to the stat without removing half of the other parts. GMs have more than enough cooling capacity and should not go above 205, mostly should stay @ 195, no matter how hard your pushing them or what the load.

Ive ran a few GM trucks over 200K and beyond 10 years and have yet to flush a radiator or change a fan, the thermostats however have been changed on every one I have ever owned.

I highly doubt the rad is plugged up or the fan is going bad....

Another thing is where are you coming up with the temp reading? The OEM gauge with stepper motors? Those are innacurate when new and in the early 00's gauge clusters and bad stepper motors were a known GM problem.

On second thought, run out and buy a diesel lol.

[LIKE2BUILD]

Pure Diesel wrote:
Check the cooling stack. Has it ever been cleaned out? Over time, miles, location, debris and bugs can block the air flow going through.

Yep, make sure the cooling stack is clear. Also as mentioned, make sure your fan clutch is working properly and flush the coolant system. If you’ve never serviced the coolant you could have sludge that’s reducing flow. Don’t go to a cooler thermostat, this will throw off the computer.

When you’re climbing a hill you should head a roar like a siren when the fan clutch locks up. If you don’t hear that it probably means your clutch is bad.

[jkilroy]

Seamutt wrote:
It should not overheat, get the cooling system flushed and inspected. Also never use tap water only distilled water. Tap water will leave behind deposits inhibiting efficient cooling.

It’s not overheating just getting warmer than normal. As soon as I turn a/c off it’s fine. Temps go back to normal pulling up incline.

[Pure_Diesel]

Check the cooling stack. Has it ever been cleaned out? Over time, miles, location, debris and bugs can block the air flow going through.

[morphrider]

I have an 01 with the 6.0. As stated above, don't lug it, these are high rpm for the hp. We assume you are using the tow haul mode?

[KD4UPL]

Fan clutch and coolant flush are good ideas. What do you mean "set the RPM at 3,000"? If your heavily loaded and going up hill that is a bit low on RPMs. You may simply be lugging it to deatb,thus creating extra heat. Look up where peak torque is on your engine. I suspect it's over 4,000. That's more where you should be running if really working it hard.

[Seamutt]

It should not overheat, get the cooling system flushed and inspected. Also never use tap water only distilled water. Tap water will leave behind deposits inhibiting efficient cooling.

[Dave_H_M]

Buy a diesel to fix the problem - i don't get it.

Sort out that fan clutch issue and if it is working then your radiator probably needs attention.

[Halmfamily]

Bessie-Hunter wrote:
Have the fan clutch checked. May not be engaging, pulling more air through the radiator for better cooling.

X2, had a bad fan clutch on our 06 Power Stroke and would overheat when pulling an incline, outside of that no cooling issues. When the fan clutch fully engages you will know it, should sound an airplane taking off under your hood.

[jkilroy]

tred0956 wrote:
Try some Water Wetter or other brand coolant additive, I think I used Royal Purple Ice, made a difference in my Class C with the 6.0

Bessie-Hunter wrote:
Have the fan clutch checked. May not be engaging, pulling more air through the radiator for better cooling.

I’ll try this

[Bessie-Hunter]

Have the fan clutch checked. May not be engaging, pulling more air through the radiator for better cooling.

[tred0956]

Try some Water Wetter or other brand coolant additive, I think I used Royal Purple Ice, made a difference in my Class C with the 6.0

[jkilroy]

I will be soon looking at a duramax. Trick is finding a older one without rust on frame and dosent have a million miles on it.